======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.18/4325 is trying to acquire lock:
ffff888025424350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_request net/nfc/nci/core.c:148 [inline]
ffff888025424350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_start_poll+0x8c8/0xcc0 net/nfc/nci/core.c:855

but task is already holding lock:
ffff8880254255d8 (&genl_data->genl_data_mutex){+.+.}-{3:3}, at: nfc_genl_start_poll+0x1c9/0x340 net/nfc/netlink.c:826

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&genl_data->genl_data_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       nfc_urelease_event_work+0x120/0x310 net/nfc/netlink.c:1833
       process_one_work+0x867/0xff0 kernel/workqueue.c:2310
       worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
       kthread+0x42e/0x520 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #2 (nfc_devlist_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       nfc_register_device+0x38/0x300 net/nfc/core.c:1116
       nci_register_device+0x89f/0x9f0 net/nfc/nci/core.c:1276
       virtual_ncidev_open+0x55/0xc0 drivers/nfc/virtual_ncidev.c:146
       misc_open+0x31f/0x390 drivers/char/misc.c:143
       chrdev_open+0x585/0x5f0 fs/char_dev.c:414
       do_dentry_open+0x7f7/0xf90 fs/open.c:826
       do_open fs/namei.c:3616 [inline]
       path_openat+0x2718/0x2fb0 fs/namei.c:3750
       do_filp_open+0x1df/0x400 fs/namei.c:3777
       do_sys_openat2+0x14b/0x500 fs/open.c:1255
       do_sys_open fs/open.c:1271 [inline]
       __do_sys_openat fs/open.c:1287 [inline]
       __se_sys_openat fs/open.c:1282 [inline]
       __x64_sys_openat+0x135/0x160 fs/open.c:1282
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #1 (nci_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       virtual_nci_close+0x13/0x40 drivers/nfc/virtual_ncidev.c:44
       nci_open_device net/nfc/nci/core.c:544 [inline]
       nci_dev_up+0x976/0xd90 net/nfc/nci/core.c:633
       nfc_dev_up+0x15d/0x310 net/nfc/core.c:118
       nfc_genl_dev_up+0x85/0xd0 net/nfc/netlink.c:770
       genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
       genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
       genl_rcv_msg+0xd0b/0xfa0 net/netlink/genetlink.c:792
       netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2519
       genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
       netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
       netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1340
       netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1919
       sock_sendmsg_nosec net/socket.c:706 [inline]
       __sock_sendmsg net/socket.c:718 [inline]
       ____sys_sendmsg+0x5be/0x8f0 net/socket.c:2446
       ___sys_sendmsg+0x236/0x2e0 net/socket.c:2500
       __sys_sendmsg net/socket.c:2529 [inline]
       __do_sys_sendmsg net/socket.c:2538 [inline]
       __se_sys_sendmsg+0x1b7/0x2a0 net/socket.c:2536
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&ndev->req_lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012
       lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       nci_request net/nfc/nci/core.c:148 [inline]
       nci_start_poll+0x8c8/0xcc0 net/nfc/nci/core.c:855
       nfc_start_poll+0x141/0x2c0 net/nfc/core.c:225
       nfc_genl_start_poll+0x1d7/0x340 net/nfc/netlink.c:828
       genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
       genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
       genl_rcv_msg+0xd0b/0xfa0 net/netlink/genetlink.c:792
       netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2519
       genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
       netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
       netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1340
       netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1919
       sock_sendmsg_nosec net/socket.c:706 [inline]
       __sock_sendmsg net/socket.c:718 [inline]
       ____sys_sendmsg+0x5be/0x8f0 net/socket.c:2446
       ___sys_sendmsg+0x236/0x2e0 net/socket.c:2500
       __sys_sendmsg net/socket.c:2529 [inline]
       __do_sys_sendmsg net/socket.c:2538 [inline]
       __se_sys_sendmsg+0x1b7/0x2a0 net/socket.c:2536
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

Chain exists of:
  &ndev->req_lock --> nfc_devlist_mutex --> &genl_data->genl_data_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&genl_data->genl_data_mutex);
                               lock(nfc_devlist_mutex);
                               lock(&genl_data->genl_data_mutex);
  lock(&ndev->req_lock);

 *** DEADLOCK ***

4 locks held by syz.0.18/4325:
 #0: ffffffff8d4aa0b0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:802
 #1: ffffffff8d4a9f08 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline]
 #1: ffffffff8d4a9f08 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x161/0xfa0 net/netlink/genetlink.c:790
 #2: ffff8880254255d8 (&genl_data->genl_data_mutex){+.+.}-{3:3}, at: nfc_genl_start_poll+0x1c9/0x340 net/nfc/netlink.c:826
 #3: ffff888025425190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline]
 #3: ffff888025425190 (&dev->mutex){....}-{3:3}, at: nfc_start_poll+0x4f/0x2c0 net/nfc/core.c:208

stack backtrace:
CPU: 1 PID: 4325 Comm: syz.0.18 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 nci_request net/nfc/nci/core.c:148 [inline]
 nci_start_poll+0x8c8/0xcc0 net/nfc/nci/core.c:855
 nfc_start_poll+0x141/0x2c0 net/nfc/core.c:225
 nfc_genl_start_poll+0x1d7/0x340 net/nfc/netlink.c:828
 genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0xd0b/0xfa0 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2519
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 ____sys_sendmsg+0x5be/0x8f0 net/socket.c:2446
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2500
 __sys_sendmsg net/socket.c:2529 [inline]
 __do_sys_sendmsg net/socket.c:2538 [inline]
 __se_sys_sendmsg+0x1b7/0x2a0 net/socket.c:2536
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f5178b470d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5178186028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f5178dcf090 RCX: 00007f5178b470d9
RDX: 0000000000000000 RSI: 0000200000000180 RDI: 0000000000000005
RBP: 00007f5178bde024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5178dcf128 R14: 00007f5178dcf090 R15: 00007ffedfe39be8
 </TASK>
nci: __nci_request: wait_for_completion_interruptible_timeout failed -512